<?php 
$search_text = get_search_query();
if (!$search_text){
	$search_text = __('search...','custom_theme');
}

$form = '<form role="search" method="get" id="searchform" class= "search_form" action="' . home_url( '/' ) . '" >';
$form .=  '<input type="text" value="' . $search_text . '" name="s" id="s" class = "search_query"/>';
$form .=  '<input type="submit" id="search_submit_button" class = "search_submit_button" value=""/>';
$form .=  '</form>';
echo $form;
?>